SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9dad7a6fd89c4ab42941f3262561b4906fbb0362a4c1ae758825f9ee6c689068' 
  AND token = 'SC+E301rovTTMWkg5YnPEg8WmXVOLYxMZ28KFlBfAyk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}